The origin of 125I and 129I in sheep thyroids from Birmingham, UK

In this paper the recently reported presence of 125I and 129I in Birmingham slaughtered sheep in 1993 is confirmed. This can be adequately explained by earlier work showing the presence of 125I and 129I in more limited areas than the report would suggest. The 129I must derive from grass grazed in an area centred on the nuclear reprocessing work at Sellafield, Cumbria and extending out to at least 96 km. Iodine-125 derives from water drunk either directly from rivers mainly in the east Midlands and Thames Valley contaminated with low levels of waste 125I, or from mains water extracted from these rivers.